Two piece electrical and fluidic connector and installation method therefore

ABSTRACT

In water cooled electric generators, an electrical and fluidic connector connects a stator bar to an electrical bus and to a water source. The connector comprises two pieces, a clip and a sleeve. During installation, the sleeve is brazed to the stator bar in a fluid tight manner, and the clip is then brazed to the sleeve. Fluidic connection from the generator&#39;s water source to the stator bar is provided by a hose attached to a fluid port on the clip. Connection to the electrical bus of the generator is provided by copper leaves and/or copper piping brazed onto the clip. The clip and the sleeve are both formed from copper to form an electrical connection between the copper leaves and/or copper piping and the stator bar. The connector may be further used to replace a defective electrical and fluidic connector that terminates a stator bar in a water cooled electric generator.

This application is a continuation of application Ser. No. 08/685,106filed Jul. 23, 1996 which application is now U.S. Pat. No. 5,616,040which is a continuation of application Ser. No. 08/405,225, filed Mar.16, 1995, which application is now issued U.S. Pat. No. 5,573,414.

TECHNICAL FIELD

The present invention relates in general to electrical and fluidicconnectors. More specifically, the present invention relates to anelectrical and fluidic connector for use in terminating a stator bar ina large electric generator and an installation method therefore.

BACKGROUND OF THE INVENTION

Large electric machines present unique engineering challenges. Forexample, the operational cooling of electrical generators used in largefossil and nuclear power generation plants is a particularly interestingproblem. Of the many parts requiring cooling in large electricgenerators, cooling the stator bars is of significant importance. Thestator bars carry most of the electrical power generated and thereforeheat up very quickly due to, for example, general ohmic losses, I² Rlosses and eddy current losses. For many years, stator bars have beenwater cooled by circulating ultra-pure deionized water therethrough.This water travels out of the generators to cooling arrays where heat isremoved, and is then recirculated to the generators in a closed loopsystem. One example of such a water cooled generator is a GeneralElectric Corp. model 4A4W2 electric generator.

Stator bars conventionally comprise multiple strands. These strands aregenerally rectangular and are composed of an electrically conductivematerial such as, for example, copper. They are grouped together to formrectangular stator bars. The strands are individually insulated fromeach other within a stator bar to reduce eddy currents and associatedlosses. However, the strands of the stator bars are typically brazedtogether at their ends to facilitate electrical connection and liquidseal therebetween. To provide cooling, at least several strands withinthe stator bar are hollowed such that cooling water may passtherethrough.

Since the stator bars carry most of the electrical power in generators,electrical connection thereto is necessary to extract electrical powertherefrom. Further, a facility for introducing and removing coolingwater from each stator bar is necessary. The traditional device forsimultaneously providing these electrical and fluidic functions is asingle piece electrical and fluidic connector shown, for example, inFIG. 1 as connector 11. This single piece connector provides: 1)electrical connection from a stator bar 19, through its own copper body(i.e., connector 11) and through a set of copper leaves 17 (and/orcopper piping in, for example, a series loop system) to an electricalbus in the generator; and 2) fluidic connection from the water carryingstrands in stator bar 19, through an inner chamber to a fluidicconnector 15 where the water is passed to a hose for transfer.

Water cooling of stator bars is not without problems, however. Oneparticularly serious problem is water leakage. Due to the high volume ofwater passing through the stator bars, even a small leak can lead to alarge volume of water entering areas of the generator in which water isundesirable. This can eventually lead to a catastrophic failure of thegenerator comprising, for example, a ground fault. Furthermore, leaksare very often hard to find because the stator bars are buried withinlarge amounts of insulation deep within the electrical generator.

The conventional electrical and fluidic connector 11 discussedhereinabove has a propensity towards water leakage. Further, once asingle water leak occurs, operational experience has shown a tendencytoward the development of additional water leaks which are known tooccur at several regions associated with the conventional connector 11.As one example, water leakage may occur at the interface between thestator bar 19 and the connector 11. This is due to the structure of theclip and associated assembly method. To explain, during factory assemblyof the generator, the individual strands composing the stator bar areinserted into an opening 20 within the connector 11. The strands arethen brazed to the connector 11 by a worker who accesses the internalbrazed areas through a small window in the connector (the window isshown covered by plate 13). This is a difficult process as space withinthe connector 11 and the access window is limited. In fact, the windowis so small that a worker will typically rely on dental mirrors andother ad-hoc brazing means to view the brazed connection being created.Thus, poor brazed connections that leak water may result. After brazingof the connector to the stator bar is completed, the window is closed bybrazing a copper plate 13 thereover. This window and associated plate 13provide yet another opportunity for water leakage. Thus, inherent in theconventional single piece electrical and fluidic connector are multipleconnections that are prone to damaging water leakage.

The conventional electrical and fluidic connector and associatedassembly techniques have a further disadvantage. Specifically, there isno way to easily replace a faulty connector while the associated statorbar is still within the generator. Therefore, a complete disassembly ofthe generator is conventionally recommended to replace a leakyconnector. Of course, this is very expensive and highly undesirable.

The present invention is directed toward providing solutions for theabove-noted problems.

DISCLOSURE OF THE INVENTION

Briefly described, in a first aspect, the present invention comprises anelectrical and fluidic connector for connecting an electro-fluidicconductor to a fluidic conductor and an electrical conductor.Specifically, the electrical and fluidic connector includes a firstmember that is electrically conductive and is configured to encircle andelectrically attach to an end portion of the electro-fluidic conductor.Further, the electrical and fluidic connector includes a second memberthat is electrically conductive and is configured for matable engagementto the first member. The second member includes a fluid port forfacilitating connection to the fluidic conductor and is configured forelectrical connection to the electrical conductor.

Furthermore, the first member and the second member define a hollowinner chamber when they are in matable engagement. In particular, thehollow inner chamber comprises a fluid tight chamber such that fluid maypass through the hollow inner chamber between the electro-fluidicconductor and the fluid port of the second member. Also, the firstmember and the second member themselves provide the electricalconnection between the electro-fluidic conductor and the electricalconductor when it is connected to the second member.

As an enhancement, the electro-fluidic conductor may comprise a statorbar that has multiple electrically conducting strands. At least one ofthe electrically conducting strands may also be adapted to conductfluid. In such a case, the first member is configured to electricallyattach to an end portion of the plurality of electrically conductingstrands.

In an other embodiment, a method is disclosed for coupling theelectrical and fluidic connector to the electro-fluidic conductor. Themethod comprises securing the first member to the electro-fluidicconductor such that the first member encircles an end portion of theelectro-fluidic conductor, forms a fluid tight seal thereto andelectrically connects therewith. The method further includes matablyconnecting the first member to the second member to form theabove-described hollow inner chamber.

As an enhancement, the method may include removing a defectiveelectrical and fluidic connector from the electro-fluidic conductorbefore connecting the first member thereto. Further, the method mayinclude verifying the fluid tight seal that connects the first memberand the electro-fluidic conductor.

The techniques of the present invention have numerous advantages andfeatures attributable thereto. Specifically, the techniques disclosedherein facilitate the replacement of a defective electrical and fluidicconnector for a stator bar while the stator bar is still within theelectric generator. This advancement results in a cost savings as thesteps required to physically remove stator bars are expensive comparedto an "in machine" repair. As a further advantage, the connector of thepresent invention provides more fluid tight seals that are more easilyverifiable. Moreover, repair of the connector is easily facilitatedusing the techniques disclosed herein. Thus, the techniques of thepresent invention improve the reliability of, and repair processassociated with, the electrical and fluidic connectors that terminatewater cooled stator bars in large electric machines.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter that is regarded as the present invention isparticularly pointed out and distinctly claimed in the concludingportion of the specification. The invention, however, both as toorganization and method of practice, together with further objects andadvantages thereof, may best be understood by reference to the followingdetailed description taken in conjunction with the accompanying drawingsin which:

FIG. 1 is a perspective view of a conventional electrical and fluidicconnector used to terminate a stator bar;

FIG. 2 is a perspective view of one embodiment of the electrical andfluidic connector of the present invention in combination with a statorbar and electrical connection leaves;

FIGS. 3 and 4 are a front view and a side view, respectively, of thesleeve portion of an electrical and fluidic connector of FIG. 2 inconformance with one embodiment of the present invention;

FIG. 5 is a side view of the electrical and fluidic connector of FIG. 2after assembly, according to an embodiment of the present invention;

FIG. 6 is a cross-sectional view of a pressure test fixture that isaffixed to a completed sleeve and stator bar assembly according to oneembodiment of the present invention;

FIGS. 7 and 8 are a front view and a side view, respectively, of thesleeve and stator bar assembly of FIG. 6, pursuant to an embodiment ofthe present invention; and

FIGS. 9 and 10 are a front view and a side view, respectively, of analternate embodiment of the sleeve portion of the electrical and fluidicconnector of the present invention;

FIG. 11 is a side view of an assembled electrical and fluidic connectorthat used the sleeve of FIGS. 9 and 10 according to one embodiment ofthe present invention;

FIGS. 12 and 13 are a front view and top view, respectively, of anassembled electrical and fluidic connector that attaches to copperpiping according to an embodiment of the present invention; and

FIGS. 14A-14B are flow diagrams of a method for providing an electricaland fluidic connector on a stator bar in accordance with an embodimentof the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Shown in FIG. 2 is a perspective view of one embodiment of anunassembled electrical and fluidic connector 12 of the present inventionin combination with stator bar 19 and electrical connection leaves 17.The connector 12 is composed of two members, a first member referred toherein as a "sleeve" 21 and a second member referred to herein as a"clip" 23. The sleeve 21 is designed to tightly encircle the end ofstator bar 19. Specifically, when the end of the stator bar has itsinsulation removed to expose the strands therewithin that compose thestator bar, the sleeve 21 may be brazed directly thereto. This brazedconnection forms an electrically conductive, mechanically rigid andfluid tight connection between the sleeve 21 and the stator bar 19.

The clip 23 of the electrical and fluidic connector 12 is designed tomatably connect to sleeve 21. In this regard, clip 23 has an opening 24therewithin that is precisely machined to receive clip 21. Clip 23 alsohas a hollow inner chamber 25 for passing water between the fluidconducting strands of stator bar 19 and fluid port 15. The fluid port 15is adapted to receive a conventional hose 16 of the type used to mate tothe fluid port of the conventional connector 11 (FIG. 1) forfacilitating replacement thereof. The clip 23 (FIG. 2) has attachedcopper leaves 17 (and/or copper piping) that facilitate electricalconnection to an electrical bus in the generator in a manner apparent toone of ordinary skill in the art.

Preferably, both the clip 23 and the sleeve 21 of electrical and fluidicconnector 12 are composed of machined forged copper. This has manyadvantages. First, because the clip 23 and sleeve 21 are conductive,they themselves form the electrical connection between the stator bar 19and the electrical leaves 17. Further, machined parts are highlyaccurate in size so that a fluid-tight fit is ensured. Additionally, theforged copper that is machined into clip 23 and sleeve 21 has lowporosity such that leakage therethrough is reduced. To contrast, theconventional single piece electrical and fluidic connector is typicallyfabricated by a copper casting process which produces a copper connectorwith higher porosity than a machined part. Water leakage through theconventional connector itself is therefore possible.

Further detail regarding the sleeve 21 is shown in FIGS. 3 and 4. Inparticular, sleeve 21 has an opening 33 sized to fit over the end of astator bar (although some clearance is added for accommodating brazingalloy). Furthermore, the outside surface of the sleeve contains multiplecircumferential grooves 31 therein. These grooves are configured toreceive brazing alloy that is used to braze the sleeve 21 to a clipduring assembly as described in further detail hereinbelow with regardto the method of FIGS. 14A-14B. The multiple grooves are each filledwith a brazing alloy such that when inserted into the clip and heated,the brazing alloy extensively contacts areas on both the sleeve and theclip such that a highly secure connection therebetween is formed.

As an example, the front view of FIG. 7 shows the different types ofstrands within the stator bar as inserted into a sleeve 21. Both thehollow fluid conducting strands 43 and the solid strands 41 are shown.Upon initial factory assembly, the ends of the strands of the statorbars are brazed together such that electrical connection therebetween isprovided. Therefore, when inserted into, and brazed to, sleeve 21, thesleeve is electrically connected to each strand within the stator bar.

Once assembled (FIG. 5), the completed connector 12 provides anelectrical connection between the brazed together strands of stator bar19 (e.g., fluidic strand 43 and non-fluidic strand 41, see FIG. 7) andelectrical leaves 17 (and/or copper piping). Again, the electricallyconductive nature of clip 23 and sleeve 21 themselves comprises theelectrical connection. Further, the completed connector 12 passes fluidbetween the fluidic strands (e.g., fluidic strand 43), hollow innerchamber 25 and fluid port 15. Cooling water may flow through theconnector in either direction depending upon which end of the stator barthe connector is installed on. For example, if cooling water were toflow from a first end of a stator bar to a second end, the water wouldenter the fluid port of the connector on the first end, traverse theconnector, enter the stator bar and pass therethrough, enter theconnector on the second end of the stator bar and pass out of the fluidport on the connector on the second end of the stator bar. Of course,fluid flow could be reversed. Thus, the connector 12 of the presentinvention facilitates connection from an electro-fluidic conductor(e.g., stator bar 19) to a separate electrical conductor (e.g.,electrical leaves 17 and/or copper piping) and to a separate fluidicconductor (e.g., a hose 16 attached to fluid port 15--see FIG. 2).

The fluid flow may have many configurations in a generator with watercooled stator bars including, for example, a configuration wherein waterenters each stator bar from a first fluidic header to which each fluidport hose is attached. The water exits from the fluid port of theconnector on the opposite end of each stator bar where it is passed to asecond fluidic header that passes the water to external cooling arrayswhere it is cooled and thereafter recycled. This configuration isreferred to herein as a "one pass" configuration because the coolingwater passes through one stator bar in a single direction. In anotherconfiguration referred to herein as a "two pass" configuration, coolingwater exiting one stator bar via a fluid port of a terminating connectoris routed to the fluid port of a second stator bar for passage throughthe second stator bar. Upon exiting the fluid port of a connector on asecond end of the second stator bar the water is passed to coolingarrays and then recycled. One type of "two pass" configuration is knownas a "series loop" configuration. In such a machine, a single copperpipe may be used to carry both fluid and electrical current from onestator bar to a next stator bar.

In an alternate embodiment of the present invention, a tapered sleeve151 (FIGS. 9-10) is used. This tapered sleeve has a solid outer surfacewhich tapers from a first diameter 155 to a second, smaller diameter153. The taper is used to provide a tight connection when matablyengaged with a corresponding clip. Specifically, sleeve 159 matablyengages with clip 157 (FIG. 11) which has a tapered opening 160 thatcorresponds to the taper of sleeve 159. The clip 157 facilitates theattachment of copper leaves 17 and has a fluid port 15, while sleeve 159surrounds an end portion of stator bar 19 that includes strands 41 and43.

In another embodiment of the present invention, the electrical andfluidic connector of the present invention may by designed to functionin a "series loop" type configuration. In such a case, the clip 161(FIGS. 12-13) has an end portion 163 that is adapted to matably engagewith copper piping. In effect, end portion 163 is both a fluid port andis adapted for electrical connection to clip 161. Again, the copperpiping routes both cooling water and electrical current to a succeedingelectrical and fluidic connector and attached stator bar. In the exampleshown, the tapered type sleeve is shown, although the grooved typesleeve of, for example, FIG. 3 could also be used.

The techniques of the present invention provide for the removal of adefective conventional connector 11 (FIG. 1) and replacement thereofwith the new two-piece connector 12 (FIG. 2) disclosed herein. The stepsfor performing this process are described below with respect to the flowdiagram of FIGS. 9A-9B.

Once a water leak has been detected, and a suspect connector has beenidentified, insulation surrounding the connector is removed (101--FIG.9A). Specifically, the stator bars and connectors are buried deep withinlarge amounts of bulk insulation such that accessing the suspectconnector and associated stator bar requires the removal of the bulkinsulation.

After the bulk insulation is removed, the suspected leak is verifiedusing trace gas testing by steps that will be apparent to one ofordinary skill in the art (103). As an example, a trace gas test may beperformed by the following steps:

a) Drain the water in the stator cooling water system and in the statorwith at least 20 pounds of H² pressure in the generator. H² pressureshould remain in the generator during water drainage so that water doesnot enter the leak by capillary action and seal the leak.

b) After the gas is purged from the generator and replaced with air,blank off the stator winding at the top of the generator.

c) "Burp" the remaining water from the winding by pressurizing thewinding with high quality (instrument) air, and releasing it rapidlywith a fast action valve.

d) Bottle up the stator and pull vacuum.

e) Maintain the vacuum for at least 24 hours or until the generator hasbeen disassembled enough to provide access to inspect the end turns,water header and hoses.

f) While the unit is being disassembled, review the most recent set ofstator Resistance Temperature Detector ("RTD") and Thermocouple ("TC")temperatures. Identify the highest temperature coils as leak candidates.

g) Break vacuum on the windings with SF⁶ (sulfur hexaflouride) gas andpressurize winding to 10 PSI with the gas.

h) Probe windings with a halogen leak detector. Use two detectors toverify initial findings.

i) If both detectors indicate a leak, verify the location with a liquidsoap bubble test.

j) Continue checking the remaining winding for the possibility of morethan one leak.

k) If no leaks are found with the SF⁶ at 10 psi, raise the pressure ofthe SF⁶ gas to 30 pounds. Repeat steps h-j above.

l) If the 30 pounds leak check of the winding is passed, prior toperforming reassembly, the SF⁶ should be released down to atmosphericpressure and the sealed winding pressurized to 100 PSI with instrumentair for a 24 hour pressure decay test.

The suspected leaky clip is thereby verified as defective and requiringreplacement.

At this stage in the process, a portion of a mica tape based insulationon the stator bar is removed (i.e., cut back) from the area where thestator bar meets the defective connector (105). This exposes the brazewhich joins the stator bar to the defective connector such that removalof the defective connector is facilitated. Thereafter, chill blocks(107) are installed on the stator bar near the defective connector toremove excess heat from the stator bar during the connector removalprocess. This is because the heat generated during connector removalcould damage the stator bar and/or insulation surrounding it. The chillblocks themselves are then tested for water leaks and activated. Afterconfirming the operation of the chill blocks, the water hose and copperleaves (and/or copper piping) are unbrazed from the defective connectorusing a torch brazing process to facilitate removal of the defectiveconnector itself (109).

More specifically, to remove the copper leaves and/or copper piping forthe liquid connections, a single-tipped torch brazing process may beused. Fuel for the torch comprises oxygen and propane. The copper leavesare unbrazed one at a time, then separated and rolled back using pliers.Since there are multiple leaves, it is necessary to roll back each leaftightly against the "water box" to allow enough room for all the leavesto be unbrazed. Care must be taken not to crack the leaves during theunbrazing procedure.

For liquid cooled "series loop" machines, the interconnecting copperpiping must be removed. Care should be taken in removing the tubing asto not damage the adjacent series loop connections. A double-tippedtorch, using propane and oxygen fuel, normally works best for thisprocedure.

An induction brazing station having custom made coils surrounding thedefective connector is next set up. These coils are water cooled, andare appropriately tested for leakage before use. The brazing station isactivated and the defective connector is heated (111) until it achievesa cherry red color (approximately 900-1100 degrees Fahrenheit).Temperature may be monitored using, for example, a digital thermometer.Once the desired temperature is reached, pliers are used to clamp eachside of the defective connector and slowly remove it from the stator bar(113). Upon removal, the power to the induction heater is discontinuedand the chill blocks are checked to ensure that they are properlycooling the stator bar. If unusually high temperatures were required toremove the defective connector, then cool air may be blown through thestator bar from the opposite end to enhance cooling.

After cooling to ambient temperature, the exposed ends of the strandsthat compose the stator bar may now be polished (115) such that excessbrazing alloy is removed therefrom. This may be performed by manypolishing processes such as by using a polishing wheel manufactured bythe 3M Corporation of St. Paul, Minn., under the brand name Scotchbrite.

The exposed strands of the stator bar are ready for fitting into thesleeve of the connector of the present invention (117). Accordingly, thestrands are wrapped with a brazing alloy ribbon (sometimes referred toherein as a "strand" brazing alloy) such that they fit tightly into thesleeve. As an example, an American Welding Society ("AWS") B-CUP 5designation brazing alloy ribbon may be used. The brazing alloy ribbonshould be applied to the strands such that there are no gaps in the fitto the sleeve. After the sleeve is fit, stainless steel pins that aresized to tightly fit into the open ends of the fluid carrying strandsare lightly tapped into each fluid conducting strand (119) to preventthe brazing alloy from flowing into the fluid openings of the strandsand clogging them during brazing.

The induction brazing station is again set up, however, this time thecoils used are custom designed to fit around the sleeve of the connectorof the present invention (coils for either the tapered sleeve or groovedsleeve are used). Again, the system is checked for water leaks prior touse. The induction brazing station is activated (121--FIG. 14B) and thesleeve is heated until alloy begins to flow (approximately 1200 degreesFahrenheit). Stick brazing alloy of similar composition to the ribbonbrazing alloy is added to the front and back of the sleeve duringbrazing to ensure a good connection. Furthermore, brazing alloy isapplied to the face of the strands to ensure that they are properlybrazed together. As a general note, care should be taken to avoidgetting brazing alloy on the outside of the sleeve such that the precisefit of the sleeve into the clip is not affected. Advantageously, accessto both the front and back of the sleeve during brazing allows adequatebrazing alloy to be introduced in appropriate locations.

To continue, after sufficient alloy has been applied, the brazingstation is deactivated and the sleeve/strands assembly is allowed tocool to ambient temperature. A rag soaked in a 50% alcohol/watersolution may be wrapped around the strands and sleeve to preventoxidation and the stainless steel pins may now be removed (123). Again,to facilitate cooling, air may be blown through the stator bar from theopposite end. After completion of the above steps, the sleeve issuccessfully brazed to the strands in an electrically conductive,mechanically rigid and fluid tight manner.

To verify the fluid tight integrity of the braze, a pressure test cap(FIG. 6) comprising a front cap 51 and a rear support 61 is attached tothe sleeve 21 and stator bar 19 assembly. Specifically, the front cap 51and rear support 61 are held together by bolts 71. The front of thesleeve/stator bar is sealed to the front cap 51 by an O-ring 72. A tracegas pressure test (FIG. 9--125) is then performed of which theindividual steps will be apparent to one of ordinary skill in the art.If leaks are detected, the induction brazing station is reattached andthe braze is repeated. Once no leaks are detected following brazing, thesleeve is cleaned in preparation for brazing of the clip thereto.Cleaning may be performed by, for example, using Scotchbrite polishingwheels as discussed hereinabove.

A further step (127) in preparing the sleeve for brazing to the clipincludes fitting round brazing alloy 45 (FIG. 8) into the grooves 31 ofthe sleeve 21 (the sleeve with grooves, e.g., FIG. 4). This roundbrazing alloy 45 helps form a tight fit between the sleeve 21 and theclip and provides a large amount of brazing alloy therebetween tofacilitate a strong brazed connection to extensive areas on both thesleeve and clip. Further, ribbon brazing alloy 47 is preferably wrappedaround the outside of sleeve 21 (FIGS. 7 and 8 and is similarly wrappedaround the outside of the tapered sleeve 151 of, for example, FIG. 10).Additionally, ribbon brazing alloy is shaped into L shaped pieces andfit into the clip using flux as a temporary holder. Thus, an adequateamount of brazing alloy is provided in all contact areas between theclip and sleeve such that a strong, fluid-tight brazed connection isfacilitated.

The brazing alloy used to connect the clip to the sleeve has a lowermelting temperature than the brazing alloy used to connect the sleeve tothe strands. A lower temperature alloy (sometimes referred to herein asa "member" brazing alloy) is used so that the clip can be brazed to thesleeve without disturbing the existing braze from the sleeve to thestrands. As one example, an AWS BAG 7 designation alloy may be used toconnect the sleeve to the clip. This brazing alloy has a meltingtemperature of approximately 800 degrees Fahrenheit, while the brazingalloy used to connect the sleeve to the strands was, for example, an AWSB-CUP 5 brazing alloy with a melting temperature of approximately 1400degrees Fahrenheit.

Continuing with the process, prior to brazing, the sleeve is placed overthe clip. Since the sleeve and clip were machined to have a precise fit,the addition of brazing alloy around the sleeve and within the clip maymake matable engagement thereof difficult. To facilitate an easy fit,the clip may be slightly heated (approximately 200 degrees Fahrenheit)so that it expands. Thereafter, the clip is placed over the sleeve andis allowed to cool such that it contracts and fits tightly over thesleeve (FIG. 9B--129). This heating/expansion process may not benecessary for the tapered sleeve 151 of, for example, FIG. 10 because ofthe tapered nature of the clip/sleeve connection.

The induction brazing station is fitted with coils that conformallysurround the clip, and the station is checked for cooling water leaks.The chill blocks are set in place on the stator bar and are also testedfor cooling water leaks. After all checks have been completed, the chillblocks and the induction brazing station are activated (131), and theheat is raised to the melting point of the BAG 7 brazing alloy(approximately 900-1100 degrees Fahrenheit). During brazing, additionalBAG 7 brazing alloy may be added to the back side of the clip where itmeets the sleeve as necessary. When brazing the tapered sleeve, pressuremay be continuously applied to the clip thus forcing the clip and sleevetightly together forming a strong and fluid tight brazed connection.After the brazed connection is complete, the induction heater isremoved, and a rag soaked with water/alcohol solution is again used,this time to cover the clip.

The assembly may then be tested for leakage by attaching an air hose(133) to the fluid port of the clip and applying pressure whilemonitoring for leaks (135). If leaks exist, the brazing station isreattached and the brazing process repeated. Once a fluid tight assemblyis formed, the copper leaves (and/or copper piping) are attached to thenew clip (137) along with the water hose by a torch brazing proceduresuch that both the separate electrical and the separate fluidicconnections to the connector are established. As final steps, the tapebased insulation is reapplied to the end of the stator bar and the newtwo-piece connector. The bulk insulation is then replaced along with anyother generator parts removed during the repair process. With this, thereplacement of the defective connector is completed.

As a note, if multiple defective connectors are being replaced at thesame time, then the final leak test may be performed on all of the newconnectors at once. This could save considerable time depending on howmany defective connectors are being replaced with the two-piececonnector of the present invention.

If any of the new two-piece connectors fail, then replacement thereof isfacilitated by a method opposite to that of the installation proceduredescribed above. To summarize, first the copper leaves (and/or copperpiping) and water hose are disconnected from the connector. Assuming acomplete replacement is needed, the clip portion of the connector isthen heated to the melting point of the clip to sleeve brazing alloy andthe clip is removed. The sleeve is then heated (with pins inserted) andit is removed from the strands. The assembly process then moves forwardas described hereinabove such that replacement is achieved. Of course,if a leak can be cured at any intermediate stage of disassembly bysimply rebrazing, then further disassembly is not required.

As a further note, the two-piece connector of the present invention maybe used in the initial fabrication of generators. Due to the higherquality brazed connections between the stator bar and the new two-piececonnector, as well as the high quality connections between the clip andsleeve of the connector itself, the connector of the present inventionwill initially form a more fluid-tight connection such that lessfrequent repair should be necessary. However, if repair does becomenecessary, such repair is readily performed as disclosed hereinabove.

To briefly summarize, the techniques of the present invention havenumerous advantages and features attributable thereto. Specifically, thetechniques disclosed herein facilitate the replacement of a defectiveelectrical and fluidic connector attached to a stator bar while thestator bar is still within the electric generator. This advancementresults in a cost savings as a conventional connector repair processrequires the stator bars to be physically removed from the generator.This type of repair process is expensive compared to an "in machine"repair. In fact, some electric generator manufacturers recommend a fullrebuild of a generator when connectors require replacing. Such areplacement has an excessively high cost associated with it. As afurther advantage, the connector of the present invention provides amore fluid tight connection. Moreover, repair of the connector is easilyfacilitated using the techniques disclosed herein. Thus, the techniquesof the present invention improve the reliability of, and repair processassociated with, the electrical and fluidic connectors that terminatewater cooled stator bars in large electric machines.

While the invention has been described in detail herein, in accordancewith certain preferred embodiments thereof, many modifications andchanges therein may be affected by those skilled in the art.Accordingly, it is intended by the appended claims to cover all suchmodifications and changes as fall within the true spirit and scope ofthe invention.

What is claimed is:
 1. An electrical and fluidic connector forconnecting an electro-fluidic conductor to a fluidic conductor and anelectrical conductor, said electrical and fluidic connector comprising:afirst member that is formed of an electrically conductive material andis configured to encircle and thereby electrically attach to an endportion of said electro-fluidic conductor; a second member that isformed of an electrically conductive material and is configured forengagement to said first member, said second member including a fluidport for coupling to said fluidic conductor and said second member beingelectrically couplable to said electrical conductor; and wherein saidfirst member and said second member define a hollow inner chamber whensaid first member and said second member are in engagement, said hollowinner chamber comprising a fluid tight chamber such that fluid is passedbetween said electro-fluidic conductor and said fluid port of saidsecond member, said fluid passing through said hollow inner chamber, andwherein said first member and said second member provide electricalcoupling between said electro-fluidic conductor and said electricalconductor when said second member is electrically coupled to saidelectrical conductor.
 2. The electrical and fluidic connector of claim1, wherein said electrical and fluidic connector and saidelectro-fluidic conductor are within a liquid cooled electric machine,and wherein said electro-fluidic conductor comprises a stator bar, saidfirst member being configured to encircle and thereby electricallyattach to an end portion of said stator bar.
 3. The electrical andfluidic connector of claim 2, wherein said stator bar includes aplurality of electrically conducting strands, at least one electricallyconducting strand of said plurality of electrically conducting strandsbeing adapted to conduct fluid, and wherein said first member isconfigured to encircle and electrically attach to an end portion of saidplurality of electrically conducting strands.
 4. The electrical andfluidic connector of claim 2, wherein said first member and said secondmember are each fabricated of machined copper such that said firstmember and said second member have a lower porosity than a porosity ofcast copper.
 5. In a liquid cooled electric machine having a pluralityof stator bars, wherein a first stator bar is coupled to a second statorbar, said first stator bar and said second stator bar each having aplurality of electrical and fluidic conductive strands extendingtherethrough, and wherein an electrical and fluidic connector isemployed in coupling said first stator bar and said second stator bar,said electrical and fluidic connector comprising:an electricallyconductive first member configured to encircle and thereby electricallyattach to an end of said plurality of electrical and fluidic conductivestrands of said first stator bar; an electrically conductive secondmember configured for engagement to said first member, said secondmember being electrically couplable to said plurality of electrical andfluidic conductive strands of said second stator bar, said second memberfurther including a fluid port; and wherein said first member and saidsecond member define a hollow inner chamber when said first member andsaid second member are in engagement, said hollow inner chambercomprising a fluid tight chamber such that fluid is passed between saidplurality of electrical and fluidic conductive strands of said firststator bar and said fluid port of said second member, said fluid passingthrough said hollow inner chamber, and when said first member and saidsecond member are in engagement electrical connection of said pluralityof electrical and fluidic conductive strands of said first stator bar tosaid plurality of electrical and fluidic conductive strands of saidsecond stator bar can be achieved.
 6. The electrical and fluidicconnector of claim 5, wherein said first member and said second membereach comprise machined copper.
 7. The electrical and fluidic connectorof claim 5, further comprising a strand brazing alloy for securing saidfirst member to said electrical and fluidic conductive strands.
 8. Theelectrical and fluidic connector of claim 7, further comprising a memberbrazing alloy for securing said second member to said first member in afluid tight manner.
 9. The electrical and fluidic connector of claim 8,wherein said strand brazing alloy has a first melting temperature andsaid member brazing alloy has a second melting temperature, said firstmelting temperature being higher than said second melting temperature tofacilitate brazing of said second member to said first member withoutmelting said strand brazing alloy.
 10. The electrical and fluidicconnector of claim 5, wherein said first member comprises a sleeve thatis configured to encircle and attach to the end of said plurality ofelectrical and fluidic conductive strands of said first stator bar. 11.A repair method for providing an electrical and fluidic connector on anelectro-fluidic conductor, said electrical and fluidic connector havinga first member and a second member that are separate and bothelectrically conductive, said second member having a fluid port forcoupling to a fluid conductor and said second member being electricallyconductive for electrical coupling to an electrical conductor, saidrepair method comprising the steps of:(a) removing an existingelectrical and fluidic connector from said electro-fluidic conductor;(b) securing said first member to said electro-fluidic conductor suchthat said first member encircles an end portion of said electro-fluidicconductor and forms a fluid tight seal thereto, and electricallyconnects therewith; and (c) securing said second member to said firstmember such that said first member and said second member define ahollow inner chamber that comprises a fluid tight chamber for passingfluid between said electro-fluidic conductor and said fluid port of saidsecond member, and wherein said first member and said second memberelectrically couple said electro-fluidic conductor to said electricalconductor when said electrical conductor is electrically coupled to saidsecond member.
 12. The repair method of claim 11, wherein said removing(a) comprises heating said existing electrical and fluidic connector tosoften an existing brazing alloy securing said existing electrical andfluidic connector to said electro-fluidic conductor such that saidremoving step is facilitated.
 13. The repair method of claim 11, furthercomprising cleaning the end portion of the said electro-fluidicconductor subsequent to said removing step (a) and prior to saidsecuring step (b).
 14. The repair method of claim 11, further comprisingverifying said fluid tight seal of said securing step (b) prior to saidsecuring step (c).
 15. The repair method of claim 14, wherein saidverifying includes affixing a test cap to said first member andpressurizing said electro-fluidic conductor such that any leaks betweensaid first member and said electro-fluidic conductor are detected. 16.The repair method of claim 11, wherein said securing step (b) comprisesbrazing said first member to said electro-fluidic conductor using afirst brazing alloy, and wherein said securing step (c) comprisesbrazing said second member to said first member using a second brazingalloy, said second brazing alloy having a lower melting temperature thana melting temperature of said first brazing alloy.
 17. The repair methodof claim 16, wherein said securing step (c) includes heating said firstmember and said second member to a temperature at least as high as themelting temperature of the second brazing alloy but lower than themelting temperature of the first brazing alloy, wherein the firstbrazing alloy does not melt during said securing step (c).
 18. Therepair method of claim 11, further comprising coupling the electricalconductor and the fluidic conductor to said electrical and fluidicconnector subsequent to said securing (c).
 19. The repair method ofclaim 11, wherein said removing step (a) comprises removing anyinsulation over said existing electrical and fluidic connector prior toremoving of said existing electrical and fluidic connector.
 20. Therepair method of claim 11, wherein said electro-fluidic conductorcomprises a stator bar in a liquid cooled electric machine, and whereinsaid securing steps (b) & (c) are performed while said stator bar isinstalled in said liquid cooled electric machine.
 21. The repair methodof claim 20, further comprising insulating the electrical and fluidicconnector subsequent to said securing step (c).
 22. The repair method ofclaim 21, further comprising prior to said insulating, performing apressure test on said stator bar and said electrical and fluidicconnector.